Expression mechanism for automatic musical instruments



Feb. 28, 1928.

C. F. STODDARD EXPRESSION MECHANISM FOR AUTOMATIC MUSICAL INSTRUMENTS Original Filed Oct. 11., 1924 ANN a a: 8 v3 an" SH awvamtoz Char/es F-5foddard elf wags a V i wind chest 4 is provided for the motor Patented Feb. 28, 1928.

UNITED STATE.

CLARLES F. STODDAED, F NEXV PANY, OF NEW YORK,

YORK, N. Y., ASSIGNOR TO AMERICAN N. Y., A CORPORATION OF NEW? JERSEY.

PIANO COM- EXPRESSION MECHANISM FOR AUTOMATIC MUSICAL INSTRUMENTS.

Application filed October 11, 1924, Serial No. 742,964.

This invention relates to automatic musical instrument and pertains more particularly to expression controlling means therefor.

It is an object of the present invention to provide apparatus which shall be capable of reproducing automatically with fidelity and accuracy the original manual performances of pianists of ability, this object being attained in part by an expression controlling apparatus in which the weight of the moving parts is reduced to a. minimum in order that more perfect regulation may be secured due to the elimination of inertia.

Other objects and advantages of the invention will appear hereinaft r.

Figure 1 is a semi-diagrammatic view of the apparatus, certain parts being shown in section to better illustrate the construction and operation thereof.

Figure 2 is a section on the line 22 of Figure 1.

Referring to the drawings, a striker or player pneumatic 1 is provided, having a sticker 2 to act upon a wippen 3 to thereby operate the usual piano action, as well understood in the art. As will be understood, a sufficient number of said pneumatics are provided to operate the entire action. A

pneumatics, each of which may be placed in communication therewith by its secondary valve 5 controlled by a corresponding primary valve 6 operated from a tracker board '7 through an appropriate duct 8 in the usual manner.

As will be understood, the force of the blow communicated to the string by the collapse of a motor pneumatic will depend upon the degree of exhaust maintained in the motor pneumatic wind chest. That is, it a high degree of exhaust is maintained in said wind chest. the collapse of the pneumatic when the secondary valve is operated to subject the pneumatic to exhaust will be more rapid than when the degree of exhaust maintained in the wind chest is less. t will thus be apparent that by varying the degree of exhaust maintained in the wind chest, the force of the blows delivered to the strings by the collapse of the motor pneumatics may be varied, and further that by n'iaintaining the degree of exhaust substantially constant, the force of the blows delivered to the trings may be maintained substantially constant.

Renewed. August 19, 1927.

In the present invention means vided for governing the degree oi exhaust maintained in the wind chest for the motor pncumatics and for thereby governing the degree of force applied to the strings or" the piano.

For the purpose oi explaining the general character of this invention, and to exemplify one practicable embodiment thereof for controlling the degree of exhaust maintained in the wind chest, the apparatus illustrated in the drawings has been selected in which the wind che t 4 is connected with a. suitable source of exhaust 13. Any of the wellknown forms of exhaust means may be employed in connection with the present invention, although it is preferable that one provided with an adjustable regulator or reservoir be used in order that the exhaust may be maintained substantially constant at any desired level.

Means are provided for subjecting the wind chest 4 to the action of the exhaust means to a greater or less extent, as for example, by restricting more or less the communication therebetween. In the specific illustrative embodiment of the apparatus here shown. a. wind way 10 connects the wind chest 4 with a chamber 11 which together with the wind chest and wind way constitute what may be called the regulated exhaust chest. A wind way 14 connects the source of exhaust 13 together with said wind way and source of exhaust may be called the high exhaust chest. Arranged to control communication between the chambers 11 and 12 is a movable member preferably of very little weight. In the present embodiment of the invention this movable member comprises a diaphragm 16 of leather, rubber cloth or other suitable material. Preferably this movable member is arranged to have one side exposed partly to high exhaust and partly to regulated exhaust. As shown, the diaphragm 16 extends over the chests 11 and 12 in position to cooperate with a wall such as the partition to control the passage of air from one chest to another, thus forming in effect a valve controlling the flow of air from the action wind chest to the source of exhaust.

Means are provided to act upon the movable member, herein the diaphragm 16, in such a manner as to increase the effect of high exhaust upon regulated exhaust as, for

are pr0- with a chamber 12 which through an adj ustably example, the partition 15. The said means herein include a chamber 17 to which one side of the diaphragm is exposed and means to maintain in said "chamber adegree of exhaust, which'for the present maybe assumed to be constant although as will later appear, this degree of exhaust may be changed for the purpose of expression variations. In the specific embodiment of the invention illustrated the chamber 17 is connected restricted passage to high exhaust and is provided with an adjustable vent to atmosphere. As will be readily understood, any-desireddegree of exhaust less than high exhaust may be maintained in the chamber 17 by the relative adjustment of the exhaust port and atmosphere vent and preferably said degree of exhaust is maintained "at a higher level than the desired degree of regulated exhaust, the precise degree maintained depending upon the particular design and arrangement of the parts. The chamber 17 may be referred to as the controlled exhaust chest and'herein is connected to the wind trunk 14 containing high exhaust by means of the passage 18 having a constriction 19 interposed thereinwhich may be adjusted to constrict The the passage to any desired degree: passage 18' has opening thereto, between the constriction 19 and the chamber 17, a duct or ducts commumcating with the atmosphere through adjustable ports which'will be later described. v

' In the preferred form of the invention illustrated, the chambers or'chests 11, 12 and 17 may be-conveniently formed in the block 20, comprising the-parts 20 and 20 in the form of. cylindrical depressions and the partition 15 may comprise an annularmember mounted in the part 20 as shown. As Will be observed, the exhaust in the regulated exhaust chest 11,the high exhaust chest 12,

and'the controlled exhaust chest 17, each act to a greater or less extent on the flexible diaphragm 16 to control the position and operation thereof, and it will be apparent,

in view of the fact that' 'the' diaphragm 16 inay be made of fairly light material, almost without inertiapthat the position and operation of the diaphragm 16 will be substantially dependent upon the resultant of ofthe motor pueuniatics before collapse is thepneumatic forces acting thereon.

The differential between high exhaust in chest '12 and controlled exhaust in chest 17 acting upon that part ofthe diaphragm exposed to high exhaust, will exert a substantially'constantupward'pull tending to pull the diaphragmagainst the edge of the par tition 15, thus tending to restrict com1nunication between the high and regulated exl1aust=-chests. On-the other hand, the differential between regulated exhaust in chest 11 andcontrolledexhaustin chest 17, actto urge the diaphragm away fronr ingupon that part of the diaphragm exposed to regulated exhaust, exerts a downward force tending to pull the diaphragm awav from the edge to enlarge communicationbetween the regulated exhaust chest and lated exhaust will also be'maintained substantially constant, because if, for example, regulated exhaust tends to increase then the downward force of the ditferential between regulated exhaust and controlled exhaust is decreased and a tendency toward airupward movement of the diaphragm results. This in turn tends to restrict communication between the high and regulated exhaust chests permitting regulated exhaust to decrease by the influx of air until the condition of equilibrium is restored. (hr the other hand if regulated exhaust tends to decrease, then the differential between regulated exhaust and controlled exhaust tends to increase with the result that there is a tendency for the diaphragm to move away from the edge of the partition 15 to increase the efiective opening between the high and regulated exhaust, thus permitting additional air to be withdrawn from the regulated exhaust chest to thereby increase the degree'of exhaust maintained therein until the condition of equilibrium is restored. Thus there is a constant tendency on the part of the diaphragm to maintain a position such that the balanced condition shall always prevail.

In the ordinary operation of the piano, several factors act separately or may combine tending to cause variations in regulated exhaust. For exampleQthere may be more or less constant leakage of atmospheric air to the regulated exhaustchest, which, even though slight, tends to reduce regulated exhaust. "By the action just described, however, this would result in a movement of the diaphragm suflicient to permit a corresponding leakage to the high exhaust chest,' thus permitting regulated exhaustto remain substantially constan As a further exampe'in the normal op eration of the piano by the motor pueumatics 1 under control of the usual'note sheet, each the valve as it travels from one seat to a-n-j other, followed immediately by tie air that is Withdrawn from the pneumatic as it collapses.

"Due to the action just described, whenever such an inrush of air occurs, the force of regulated exhaust actmgupwardly onthe diatill '5', maintaining rather phragin thereby tends to decrease thus permitting the diaphragm to move downwardly to increase the effective opening between the edge 20 and the diaphragm, whereby a corresponding quantity of air may be withdrawn to the high exhaust chest. Consequently, there is a tendency to increase regulated exhaust until a condition of equilibrium is again reached.

Such action may take place so promptly and quickly, that, in ellect, the action is to maintain the degree of exhaust in the regulated exhaust chest substantially constant, or, in other words, the practical effect is that or than correcting. And this capacity of the apparatus to maintain a constant degree of regulated exhaust rather than to correctchanges in the regulated exhaust chest is increased over prior art structures having a similar capacity due to the fact that the diaphragm 16 is substantially without inertia. In other words, such action as occurs results almost wholly from the action or juxtaposed pneumatic forces upon each other, and there is no lag or overthrow Such as would otherwise occur with parts having substantial weight.

Thus, in the playing of a single note there may be several contributing factors tending to reduce regulated exhaust below its normal level which, it not compensated for, might reduce the force with which the blow is struck. As has been explained, however, the restoring action operates so quickly due to the absence of inertia that in practical ettect regulated exhaust is maintained substantially constant.

Obviously, in the operation of a piano the number of motor pneumatics operated during the playing of a musical composition varies widely from time to time. As will be apparent, however, due to tne action just described, the degree of exhaust maintained in the regulated exhaust chest and the wind chest will tend to remain substantially constant no matter how many motor pneumatics are operated at any given time and the elfective opening between the high and regulated exhaust chests will be automatically varied to permit the e'll'ectual removal of the air ad mitted to the regulated exhaust chest.

Thus far it has been assumed that the degree of exhaust maintained in the controlled exhaust chest 17 remains substantially con stant. and that it thus exerts a substantially constant downward pull on the diaphragm. That is, the device thus far has been considered purely a regulator. Means are provided, however. for changing the degree of exhaust maintained in the controlled exhaust chest to thereby change the degree of exhaust maintained in the regulated exhaust chest. i

Before passing to a consideration of the specific means employed to accomplish this purpose, it may be convenient to consider the etl'ect of a change in controlled exhaust on the apparatus. As has been explained, regu lated exhaust and high exhaust exert an upward pull on the diaphragm, while controlled exhaust exerts an opposed downward pull thereon. Consequently, assuming that high exhaust remains substantially constant, an increase in controlled exhaust must result in an increase in regulated exhaust in order that the condition of equilibrium ma] be maintained. That is, having increased the force acting downwardly on the diaphragm the force acting upwardly must also increase in order to maintain the condition or equilibrium. As a specilic example of what may occur under these conditions, it controlled exhaust is increased, there first results a tendency to pull the diaphragm away from the edge of the partition, thus permitting a larger quantity or air to be withdrawn from the regulated exhaust chest whereby the exhaust therein is increased. This increase in time exerts an increased upward pull on the diaphragm tending to return it toward the edge of the partition to restore the condition of equilibrium. Consequently, any change in controlled exhaust will cause :1 correspond ing change in regulated exhaust and in the degree of power applied to the strings by the hammers.

As has been set forth before, the adjustable constriction 19 may control the degree of exhaust maintained in the controlled exhaust chest 1'7, the particular degree of exhaust maintained therein being dependent on the relative sizes of the opening past this constriction and ot' the vents through which atmospheric air is bled to the controlled exhaust chest. Obviously if the size of these vents remains constant the degree of exhaust maintained in the controlled exhaust chest may remain constant, and conversely if the size of these vents is changed the degree o'l exhaust may be changed. Advantage is taken of this property in the present embodiment and changes in the degree of controlled exhaust are conveniently obtained by making the size of the vents open to atmosphere of different capacity.

For this purpose, ducts 25" and 25 are provided each of which is in communication with the conduit 18 between the constriction 19 and the controlled exhaust chest 17. The

ducts 25, 25" and 25* are connected respcctively to chests 26, 26" and 26 which are similar so that only one will be described in detail herein. The chest 26 comprises a chamber 27 and a chamber 28 said chambers being separated by a flexible diaphragm 29, the chamber 2? being normally maintained under high exhaust through a duct 30. The duct 25 is connected to the chamber 28 and the pa. sage of air therethrough is controlled by a valve 31 normally urged toward closed ill) lie

I cient'to overcome the upward 1 chamber 27 is subjected duct 25, thus causing position-by a light coil. spring 32 The strength of the spring, however, is insuffipull of the exhaust in the chamber 27 so that when the to exhaust the valve remains in raised posit-ion The duct 33 also leads to the chamber 28 and'permits the entrance thereto of air from port 34. Thus, when the chamber 27 is subjected to exhaust, the valve 31 is raisedto permit the flow 0'? air through the duct 33 into the chamber 28 and through the duct 25 to the conduit 18 and controlled exhaust chest 17 to thereby reduce the degree of ex 'haust maintained therein. If, under these conditions, atmospheric air is admitted to the chamber 27, the dilierential acting on the diaphragm 29 is reversed and the re-' sultant pneumatic force plus the force of the spring 32 will. close the valve 31 cutting off the passage of atmospheric air vto the the degree of exhaust maintained in the controlled exhaust chest to be again raised to its former level.

; At the end of the duct 33 leading 'to the chest 26 and at the ends of the correspondstrict the ducts leading ing ducts 33 and 33? leading to the chests 26 and 26 are placed the pins 35, 35" and which may be adjusted with respect to' the block 36 to conto the different chests in varying degrees. For instance, the pin 35 may be adjusted to nearly close the passage 33; the pin 35 may/be adjusted to provide a somewhat greater opening; and the pinr35 may provide a still greater open- 1n i Tt will thus be apparent that by controlling the valves 31, 31' and 31 to permit the flow of air to the controlled exhaust chest '17 through the ducts 33, 33 and 33 either separately or in various combinations, several distinct degreesof exhaust may be established'in the controlled exha'ust'chest 17 to thereby establish related distinct degrees of exhaust in the regulated exhaust chest 11.

For instance, each of the valves 31, 31? and 31 may be openedseparately or the valves 31, 31'1nay be opened together while the valve 31 remains closed or the valves 31 and 31 may be opened .while the valve 31 remains closed or the valves 31 and 31 may be opened while the valve 31 remains closed, or all of the valves may be opened together. In each case a different degree of exhaust would be established in the controlled exhaust chest and a corresponding different degree of exhaust would be established in the regulated exhaust chest.

It is to be understood, however, that whatever the degree of exhaust established by i the operation of the valves in the controlled exhaust chest anew condition of equilibrium is thereby set up andthe new degree of exhaust established in the regulated exhaust chests 26, 26" and 26 V is cut as.

chest will be maintained substantially constant by the-regulating actionot' the diaphragm'16 before described; r

Means are also provided for controlling the condition of the chambers 27 ,27 and 27",--that is, controlling the admission of For this purpose a series of three valve act-ions is of which controls one of the before described, and since each of these controlling valve actions is ofthe same construction only one will be described in detail herein. 7

The duct 30 connects the chamber 27 vwith a valve chamber 41 which is controlled by a duplex valve 42 43 to atmosphere and a port 44'leading to the exhaust chest 45 connected to the high exhaust chest 46 by means of the passage 47 The high exhaust chest 46 is connected to the wind trunk ,y means of the duct- 48. The valve 42 is controlled and operated by a diaphragm 49- covering the diaphragm chamber 50 into which opens the duct 51 leading to the tracker bar 7. When the tracker bar vent 52 controlling the admission of atmosphere to the duct 51 isopened the differential of pressure between the diaprovided each phragm chamber 50 and the exhaustchest 3' arranged to control a port 45 causes the valve 42 to be raised to close the port 44 to thereby cut off exhaust from the chamber 27 and to open the port 43 to ion the tracker vent 52 closed and the valve 42 lowered,"the chamber 27 is maintained underexhaust from the exhaust vchest 45 and when the valve'42 is raised atmospheric air is admitted to the chamber '27 and exhaust When the valve 42 is once raised by ventmg the tracker duct 51, the valve preferably remains in raised position even though the tracker vent may be immediately closed. In 1 the specific apparatus illustrated this results from the fact that once the valve 42' is open to admit atmosphere to the valve chamber 41, said valve 42 is held in that position by atmosphere admitted past the valve 42 into a duct 61 from which it passes through 'a' bleeder vent 62through the duct 63 which communicates with the diaphragm chamber 50. Thus, so long as atmosphere is'admitted through the duct 61 the diaphragm 49 will remain lifted and atmosphere will continue to be admitted to the chamber 27. v V

From the preceding discussion itwill appear that small perforations in a note sheet controlling the tracker vents 52, 52" and 52 may be employed which may be immediately closed if desired. When u-sed'withthelillustrative apparatus, each such perforation has the effect of introducing atmosphere to one of the chambers 27, 27 and 27 and even after the tracker vent is closed atmosphere will continue in the corresponding chamber until purposely exhausted at any subsequent time in a manner such as that about to be described.

In the preferred embodiment of the apparatus illustrated in the drawings, a single valve mechanism controlled by a single tracker vent is employed to cooperate with all or any of the three above described valve mechanisms to negative the effect of opening one or more of the tracker vents 52, 52 and 52 Such valve mechanism is desig nated in the drawings by 71. This valve mechanism comprises a valve chamber 72 controlled by a duplex valve 73 arranged to open the port 74 to atmosphere and to close the port 75 to exhaust from the exhaust chest 7 6 connected to the high exhaust chest 46 by means of the duct 77. The valve is operated by a diaphragm 78 mounted over the diaphragm chamber 79 which COll'lIIlUDicates by means of the duct 80 with a tracker vent 81.

lVhen the tracker vent 81 is opened by a suitable opening in the note sheet. atmosphere is admitted to the diaphragm chamber 79 and the differential of pressure between the diaphragm chamber and the exhaust chamber 76 causes the valve 73 to be raised to cut off exhaust from the valve chamber 72 and to permit atmospheric air to enter the chamber.

As already stated, the valve 42 is held in raised position by the atmosphere which is admitted to the diaphragm chamber 50 through the ducts 63 and 61. As will be apparent, if communication between these ducts is cut oii' and suction applied to the duct 63, the differential of pressures which caused the valve 42 to be raised would be equalized and the valve 4-2 would return to its normal position. Means are provided accordingly for performing this operation, such means comprising the valve 85 which normally remains in seated position covering the port 86 leading to the exhaust chamber 45. If this valve is raised, the port 86 will be closed thus cutting off communication between the ducts 61 and 63. At the same time the valve chamber 87 will be subjected to exhaust through the port 80 and this exhaust, communicated through the bleed vent 62 and the duct 63 will cause the valve 42 to return to norn'ial position as before described.

The valve 85 is operated by a diaphragm 88 covering the diaphragm chamber 89 which is in communication with the valve chamber 72 before described through the duct 90. Accordingly, when the valve 73 is in its lowered position the diaphragm chamber 89 .is subjected to exhaust and the valve 85 remains in loweredposition. lVhen the valve 7 3 is raised by the admission of atmospheric air through the tracker vent 81, atmospheric air is also admitted to the diaphragm chamber 89 with the result that the valve 85 is raised and the valve 42 is returned to normal position. In this manner by opening the-tracker vent 81 any of the chambers 27, 27 and 27 which have been opened to atmospheric air are again subjected to exhaust.

The operation just described, so far as it concerns the specific illustrative mechanism, depends upon bleeding the diaphragm chamber 50. It the tracker duct 51 be opened through its vent 52 at the time the vent 81 is opened to initiate the bleeding of the diaphragm chamber 50, atmosphere will enter the chamber 50 more rapidly than it can be exhausted therefrom by the described bleeding, and therefore the effect of opening the vent 81 is negatived and under such circumstances the valve 4-2 will remain in raised position and atmosphere will continue to be admitted to the chamber 27.

Also, if the tracker vent 52, for instance, be opened simultaneously with the tracker vent 81, the latter will inaugurate a tendency to bleed the chamber 50 and keep the valve 42 lowered in the position shown, but the simultaneous Opening of the tracker vent will admit atmosphere to the chamber 50 more rapidly than it can be exhausted by the bleeder and therefore the valve 42 will be lifted in spite of the opening of the tracker vent 81.

From the above description it will be understood that whether or not the tracker vent 81 be opened, the opening of any of the vents 52, 52 and 52" will have its normal and usual effect to admit atmosphere to the appropriate chamber 27 2", 27". This will be true if any vent 52, 52, 52, be opened with or without simultaneously opening the tracker vent 81.

On the other hand, if the vent 52 be opened and then closed, atmosphere being thereby admitted to the chamber 27, and the vent 81 be thereafter opened, the previous effect of opening vent 52 will be negatived and the chamber 27 will be opened to exhaust.

The apparatus thus far described has the capacity of maintaining in the regulated exhaust chest a substantially constant degree of exhaust regardless of the number of motor pneumatics operated at any given time, and regardless of the varying amounts of air admitted to the regulated exhaust chest therefrom. It likewise has the capacity of varying the degree of exhaust maintained in the regulated exhaust chest by a series of substantially distinct steps or increments which produce similar distinct steps" or increments in the intensity of the haust maintained varying force ofthe blowsimpart'ed' tothe strings by the hammers.v As has also been noted, the degree of exhaust established in the reg 'lated exhaust chest will be maintained substantially constant'at any of the severaldegrees atwhich it may be setby changing thedegree of exhaust inthe con-- trolled'exhaust chest.

Means are alsolprovided for varying the degree of exhaust maintained in'the regulated exhaust chest not only by distinct incrementsor steps, as has previously been described, but also for varying the degree of regulated exhaust by substantially continuous progression in' order to simulate the crescendo and 'diminuendo effects which form a part ofthe-art ofskilledpianists. In the present embodiment this desideratum is attained by varying the degree of exin the controlled exhaust chest by substantially continuous progres- 'sion just as in the previous description in.- cremental changes in regulated exhaust were obtained by varying controlled exhaust by substantially distinct increments. 36 carrying the pins 35, and 35", before described is mounted on the shaft 103 supported by the fixed leaf 104: of the pneumatic 105 and by a fixed block 106, the shaft being adapted to reciprocate therein in order that the pins may be moved backward and forward with respect to the openings 3 1, 34 and 3 1*. It will be observed that the pins are tapered .so that if the pins are moved to the right away from the ports34, 3 1 and 3 1 a less degree. of constriction is effected than if the pins are movedto the left.- It will also-be apparent that if the pins aremoved from right to left with a 'continuousmovement, the degree of ,constriction imposed" by the pins will be continuously and progressively increased, and conversely ifthe pins are moved from left I to right the degree of constriction imposed by the pins will be continuously and progressively lessened; A spring 107 is attachedto the shaft 103 to exert a continuous pull toward the right to normally urge the; pins in thatdirection. 1

Means are provided for urging the pins.

such means controlled from the tracker bar by a note sheet. For this purpose the movable lea-f 108 of the pneumatic 105. is 1 extended, outwardly into engagement with an adjustable collar 109 in the opposite direction and mounted on the shaft! 103. Collapse of the pneumatic will urge the pins to the left to further constrict the openings and expansion of the pneumatic will permit the spring 107 to return thepins to normal position. The conduit 110 leads to the pneumatic 105 and is connected at. its other end to a duct 111 The block.

. phragm duct 111 and conduit 110 to be subjected to exhaust to thereby initiate a collapsing movement of the pneumatic 105; When the valve 114 is lowered, the port 116' is closed and atmospheric air is permitted to enter through the port 115 and .is communicated to the pneumatic 105 through the duct 111 and conduit 110 to permit the pneumatic to expand.

Operation of the valve 11% is effected by means of the diaphragm 118 covering the diaphragm chamber 119 to which atmospheric air may be admitted through the ducts 120, 121 leading to the tracker vent-122. Normally, therefore, with the tracker vent 122.closed, the valve 114 is lowered and the pneumatic 105'is opened and remains in an expanded condition. hen the tracker duct 122 is opened the valve 11 1' is raised and'the pneumatic 105 is subjected to exhaust, it being understood to atmospheric air 7 that the size of the pneumatic with respect to the capacity of the ducts is such that the collapse thereof extends over an ap-' preciable period of fects. For this purpose the by-pass 12%.is

provided controlled by the valve 125 so that the rate of-flow of airjthrough' duct 111 7 may be controlled by the adjustable screw 126 instead of by the screw 123 previously described. The 'screw126 may be adjusted to provide a less degree of constriction in the duct 111 than that provided by the screw 123 so that at any time when air is being drawn directly through the. duct 111 the rate of flow therein. will be controlled by the screw 123 while at any time when the by-pass124 1S opened the rate'offlow of air'througl'i the duct 111 is controlled by the screw 126.

The valve 125' is operated by the dia- 127 mounted over the diaphragm chamber 128 and is in effect a secondary valve controlled by r the valve 129. The

valve 129 is mounted in a valve chamber 130 connected to the diaphragm chamber 128 by duct 131 and controls a port 132 to atmosphere and a port 133 to the exhaust chamber 117. When the valve is raised the port 132 to atmosphere is closed and the port 133 to the exhaust chest is opened thus permitting the diaphragm chamber 128 to be subjected to exhaust to open the valve 125 to permit the flow of air through the by-pass 12 i. lVhen the valve is lowered the port 133 is closed and the port 132 to atmosphere is opened thus admitting atmosphere to the diaphragm chamber 128. The valve 125 is caused thereby to close the by-pass 124 due to the dii'lerential of ressures between thediaphragm chamber 128 and the bypass 124. The valve 129 is operated by the diaphragm 134 covering the diaphragm chamber which is in communication with the ducts 136 and 137 leading to the tracker duct 138.

Thus, when the tracker duct 138 is closed the valve 129 remains lowered and operation of the valve 114, by opening of the tracker vent 122 under these conditions will cause a relatively slow collapse of the pneumatic 105. Similarly, if the tracker vent 122 is now closed the valve will drop permitting the pneumatic 105 to expand slowly.

On the other hand, it the valve 11 1 is operated by opening of the tracker vent 122 while the vaive 129 is also operated by opening of the tracker vent 138, the pneumatic 105 will be collapsed more rapidly due to the fact that the by-pass 124 is opened under these conditions. Similarly, if the tracker vent 122 be closed while the tracker vent 138 remains open a more rapid expansion of the pneumatic 105 is thereby permitted.

It will be observed that the apparatus described has a three-fold capacity for controlling playing intensities. In the first place, it performs a regulating function, that is, it maintains a substantially constant degree of exhaust in the regulated exhaust chest and in the wind chest regardless of the number of notes being sounded. Second, it provides for changes in the degree of exhaust maintained by the regulator in the regulated exhaust chest and action wind chest by substantially distinct increments to thereby provide incremental changes in playing intensities. Thirdly, it provides a means by which the degree of exhaust maintained in the regulated exhaust chest may be varied by substantially continuous pro gression thereby providing crescendo and diminuendo effects. It will be noted, moreover, that in each case the capacity of the apparatus to perform its function is effected through the action of the diaphragm 16 in controlling the passage of air from the regulated exhaust chest 11 to the high exhaust chest 12. The diaphragmv has a two-fold function. It acts as a throttle valve to directly control the flow of air and furthermore it serves as its own controlling means since the surfaces of the diaphragm provide the areas on which the opposed pneumatic forces act in controlling playing intensitites.

As has been previously pointed out, ti :2 diaphragm 16 is substantially without weight and, therefore, substantially without inertia. Accordingly, the device is extremely accurate and delicate in its operation and permits the extremely quick changes in playing intensities which are so highly desirable in reproducing mechanically the playing of the artist.

It is to be understood that the invention may be variously modified and embodied within the scope of the subjoined claims.

I claim as my invention:

1. Expression cont-rolling apparatus for automatic musical instrun'ients, comprising. in combination, means providing a high exhaustchest; means providing a regulated exhaust chest; means including a flexible diaphragm for controlling comn'iunication therebetween, said diaphragm having an area exposed to regulated exhaust and an area exposed, to high exhaust influencing said diaphragm in one direction: and pneumatic means tor exerting a substantially constant opposed force on said diaphragm.

2. Expression controlling apparatus for auton'iatic musical instruments, comprising. in combination, moans providing a high exhaust chest; means providing a regulated exhaust chest; means including a flexible diaphragm for controlling comn'iuuication therebetween, and diaphragm having an area exposed to regulated exhaust and an area exposed to high exhaust influencing said diaphragm in one direction; and means for influencing said diaphragm in the opposite direct-ion.

3. Expression controlling apparatus 'lor automatic musical instruments, comprising. in combination, means providing a high exhaust chamber; means providing a regulated exhaust chamber; athrottle valve controlling communication therebetween. said valve comprising a flexible diaphragm ha ing an area exposed to regulated exhaust tending to influence said diaphragm to a position to further const-rict communication between said chambers; and pneumatic means exerting a force on said diaphragm tending to influence it to a position to enlarge communication therebetween.

4. Expression controlling apparatus for automatic musical instruments, comprising, in combination, means providing a high exhanst chamber means providing a regulated exhaust chamber: a throttle valve controlling communication therebetween, sa d valve comprising a flexible diaphragm having an area exposed to regulated exhaust .edexhaust chamber; a throttle valve .munication with ed exhaust chamber; a throttle valve controlling communicatlon therebetween,

said

. 1 valve comprising a nexible diaphragm hav-' ing areas exoosed to regulated exhaust and high exhaust influencing said diaphragm in one direction; and pneumatic means for exerting an opposed substantially constant force on said diaphragm.

6. Ex )ression controllin aoaaratus for automatic musical instruments, comprising, in combination, means providing a high exhaust chamber; means providing a regulated exhaust chamber; a throttle valve controlling communication therebetween, said valve comprising aflexible diaphragm having areas exposed to regulated exhaust and high exhaust influencing said diaphragm in one direction; and pneumatic means for exerting an opposed force on said diaphragm. 7. Expression controlling apparatus for automatic musical instruments, con'iprising, in combination, means providing a high exhaust chamber; means providinga regulated exhaust chamber; a' throttle valve controlling communication therebetween, said valve comprising a flexible diaphragm hav ing areas exposed to regulated exhaust and hi gh exhaust influencing said diaphragm in one direction; and means for influencing said diaphragm in the opposite direction with a substantially constant force. 8. Expression controlling apparatus for automatic musical instruments, comprising, in combination, means providing a high exhaustchamber; means providing a regulatcontrolling communication therebetween, said valve comprising a flexible diaphragm having exposed to regulated exhaust and high exhaust influencing said diaphragm in one direction; andmeans "for influencing said diaphragm in the opposite direction.

9. Expression controlling apparatus for automatic musicalinstruments, comprising, in combination, means providing a high ex haust chest; means providing a regulated exhaust chest: a'flexible diaphragm controlling communication therebetwe'en, fluenced bythe exhaustmaintained in said chambers to close communication therebe tween; and means having constricted comsaid high exhaust chest for exerting a suband' with atmosphere diaphragm stant-ially constant forceon said in the opposite direction.

10; Expression controlling apparatus for and inautomatic musical instruments, comprising, in (JOIHbJZItlOB, means providing a lnghexhaust chest; means providing a regulated exhaust chest; a flexible diaphragm controlling communication therebetween, and influenced by the exhaust maintained in said chambers to close comn unication therebetween; and means to influence said diaphragm.

toward open position including a chamber having communication with high exhaust and atn'iosphere through constricted openings.

12. Expression controlling apparatus for automatic musical instruments, comprising, in combination, means providing a high exhaust chest; means providing a regulated exhaust chest; a flexible diaphragm controlling communication therebetween, and influenced by the exhaust maintained in sai chambers to close communication therebetween; and means to influence said diaphragm toward open position.

13. Expression controlling apparatus for automatic musical instruments, comprising, in combination, means providing a high exhaust chest; means providing a regulated exhaust chest; a flexible diaphragm controlling communication therebetween, and influenced by the exnaust maintained in said chambers to close communication therebetween; means to influence said diaphragm toward open position, and means to vary the forceexerted by said last named means.

14. Expression controlling apparatus for automatic musical instruments, comprising, in combination, meansproviding a high exhaust chest; means providinga regulated exhaust chest; a flexible diaphragm controlling communicationtherebetween, and influenced by the exhaust maintained in said chambers to close communication therebetween; means to influence said diaphragm toward open position, and means to vary the force exerted by said last named means by substantially distinct increments. V 15. Expression controlling apparatus for automatic musical instruments, comprisin in combinatiom'means providing a high ex haust chest; means providing a regulated exhaust chest; a flexible diaphragm controlling communication therebetween, and influenced by the exhaust maintained in said chambers to close communication therebetween; means to influence said diaphragm means exerting acontrolling apparatus for in combination, means toward open position, and means to vary the force exerted by said last named means by substantially continuous progression.

16. Expression controlling apparatus for automatic musical instruments, comprising, in combination, means providing high exhaust chest; means for providing a regulated exhaust chest; atlexible diaphragm controlling communication therebetween, and influenced by the exhaust maintained in said chambers to close communication therebetween; means to influence said diaphragm toward open position, and separate means to vary the force exerted by said last named means either by substantially distinct inc-rements, or by substantially continuous progression, said means being operable separately or concurrently.

17. Expression controlling apparatus for automatic musical instruments, comprising, in combination, means providing a high exhaust chamber; means providing a regulated exhaust chamber; means providing a controlled exhaust chamber, said last named ('lltlll'llI-PI' having pneumatic communication with high'exhaust through a constricted opening; and means including a flexible diaphragm to separate said controlled exhaust chamber from said high and regulated exhaust chambers and to control communication between said high and regulated exhaust chambers.

18. Expression controlling apparatus for automatic musical instruments, comprising, in combination, means providing a high exhaust chamber; means providing a regulated exhaust chamber; means providing a controlled exhaust chamber; and means to separate said controlled exhaust chamber from said high and regulated exhaust chambers and a lapted to control communication between said high and regulated exhaust chambers.

19. Expression controlling apparatus for automatic musical instruments, comprising,

providing a high exhaust chamber; means providing a regu lated exhaust chamber; and flexible means for controlling communication between said chambers having areas on which controlling pneumatic forces act.

20. Expression controlling apparatus for automatic musical instruments, comprising, in combination, means providing a high exhaust chamber; means providing a regulated exhaust chamber; and means including a flexible diaphragm to restrict more or less the communication between said chambers.

In automatic musical instrument having a main source of power and player pijieumatics, in combination, a high exhaust chest having communication with said source of power; a regulated exhaust chest aaving communication with said player pneumatics; and means including a flexible diaphragm interposed between said chests for governing communication therebetween.

22. In an automatic musical instrument having a. main source of power and player pneumatics, in combination, a high exhaust chest having communication with said source of power; a regulated exhaust chest having communication with said player pneumatics; and means including a flexible diaphragm interposed between said chests and suspended between opposed pneumatic forces for governing communication therebetween.

In an automatic musical instrument having a main source of power and player pneumatics, in combinat on, a high exhaust chest having communication with said source of power; a regulated exhaust chest having communication with said player pneumatics; and a flexible diaphragm acting to throttle pneumatic communication therebetween, said diaphragm being exposed to opposed'pneumatic forces controlling the degree of said throttling.

In an automatic musical instrument having a man source of power and player pneumatics, in combination, a high exhaust chest having communication with said source of-power; a regulated exhaust chest having communication with said player pneumatics; a controlled exhaust chest having communiition with high exhaust and atmosphere through constricted openings; means controlling commr'mication between said high and regulated exhaust chests and influenced in one direction by the exhaust in said chests and influenced in an opposite direction by the exhaust in said controlled exhaust chest; and means to vary the exhaust in said controlled exhaust chest to vary the d fferential of pres ures acting on said cont-rolling means exhaust.

to thereby vary regulated automatic musical instrument 25. In an having a main source of power and player pneumatics, in combination, a high exhaust chest having communication with said source of power; a regulated exhaust chest having communication with said player pneumatics a controlled exhaust chest having communi cation with high exhaust and atomosphere through constricted openings; means controlling con'ununication between said high and regulated exhaust chests and influenced in one direction by the exhaust in said chests and influenced in an opposite direction by the exhaust in said controlled exhaust chest; and means to the exhaust in said controlled exhaust chest by substantially dis tinct increments to vary the diflerentialof pressures acting on said controlling means to thereby vary re ulated exhaust incremen tally.

26. In an automatic having a main source of power and player musical instrument.

commani -ation with said player pi'ieumatics; means controlling commuuication between said chests having an area subjected to high. exhaust and a dilicrent area subjected to regulatedexhaust, each of said exhaustsexerting a iiorce influencing said means in the same direction; and pneumatic means for exerting a substantially constant force thereon in the opposite direction.

of newer: a re ulated exhaust chest havin i c a 28. In an automatic mus cal instrument having a main source of power and player pneumatics, in combination, chest having communication with said source of power; a regulated exhaust chest having communication With said player pneumatics; means controlling communication between said chests having an area subjected to high exhaust and a dili'erent area subjected to regulated exhaust, each of said exhaustscxerting a force influencingsaid means in the same direction; means for exerting a substantially constant force thereon ill the opposite direction; and means for varying the degree. of force applied by said last named means. I

In anautomatic musical instrument having a main-source of power and ilayer pneumatic-s, in combination, a high exhaust chest having communication with said source of power; a regulated exhaust chest having substa 'itially distinct. increments.

c=: n'1munication with said player pneumatics; cans controlling communicationbetween sad chests having anarea sub ected to high exhaust and a diii'erent area, subjected to regulated exhaust, each of said exhausts ex: crting a it'orceinfluencing said means in the same direction; means for exerting. a substantially constant force thereon in the opposite direction; and means to vary the force exerted by said last'named means'by 30. In an automatic. musical instrument having a'inain source of power and player pneumatics, in combination, a high exhaust chest having cormnunication with said source otpower; a regulated exhaust chest having communication with said player pneumatics; means controlling communicaa regulated exhaust chest having 7 said means in the a high exhaust regulated exhaust chests being determined ice-0,63

sub-

area

lion between said chests having an. area jected to high exhaust and a differentsubjected to regulated exhaust. each of said exhaustsexerting a force influencing" said means in the same direction; means for exerting a substantially constant force thereon in the opposite direction; and means to vary the force exerted by said last named means by substantially continuous progression.

31. In an automatic musical instrument having a main source of powerand player pneumatics, in combination, a high exhaust chest having communication with said source of power ;a regulated exhaust chesthaving comn'mnication with said player pneumatics; means controlling coinmunication between said chests having an area subjected'to high exhaust and a ditl'erent area subjected to regulated exhaust, each of said exhausts exciting a force influencing said means in the 7 same direction; means tor exerting a substantially constant force thereon in the opposite direction; and separate means to vary the force exerted by said last named means either by substantially distinct increments,

or by substantially continuous progression, said means being operable separately or concurrently. 7

32. In an automatic musical instrument having a main source of power and player neumatics, in combination, a high exhaust chest having communication with "said source of power; having con'imunicat-ion with said player pneumatics; a controlled exhaust chest having constricted commimication with said source of power; and means controlling communication" between said regulated and high exhaust chests and influenced by the exhausts in all of said chests in such manner as to maintain a substantially constant degree of exhaust in said regulated exhaust chest. 7 1 i I i In an automaticmusical instrument having a; main source of power and player pneumatics; in combination, a-high exhaust chest having communicatioir with "said a regulated exhaust chest i source of power; a regulated exhaust chest having communication "with said player pneumatics; a controlled exhaust chest haring constricted communication with said high and regulated exnaust chests and in fluenced in opposite. direction by the ex- L the haust in said controlledexhaust chest,

effective constriction imposed by said means on the communication between saidhigh and by the resultantof the differentials olpressure in the chests acting thereon.

8%. In an automatic musical instrument having a main source of power and player pneumatics, in combination, a high exhaust chest having communication with said source of power; a regulated exhaust chest having communication with said player pneumatics; a controlled exhaust chest having constricted communication with said source of power and atmosphere; and means controlling communication between said regulated and high exhaust chests and influenced in one direction by the exhausts maintained in said high and regulated exhaust chests and influenced in an opposite direction by the exhaust in said controlled exhaust chest, the effective constriction imposed by said means on the communication between said high and regulated exhaust chests being determined by the resultant of the differentials of pressure in the chest-s acting thereon; and means to vary the degree of exhaust maintained in said controlled exhaust chest to thereby vary the degree of ex haustmaintained in said regulated exhaust chest.

In an automatic musical instrument having a mam source of power and player pneumatics, in combination, a high exhaust chest having communication with said source of power; a regulated exhaust chest having communication with said player pneumatics; a controlled exhaust chest having constricted communication with said source of power; means controlling communication between said regulated and high exhaust chests and influenced by the exhausts in all of said chests in such manner as to maintain a substantially constant degree of exhaust in said regulated exhaust chest; and means to vary the degree of exhaust maintained in said controlled exhaust chest to thereby vary the degree of exhaust maintained in said regulated exhaust chest.

36. In an automatic musical instrument, a main source of power; a player action; means providing a windway connecting the two; and regulator means including a flexible diaphragm interposed in said windway for controlling communication therebetween.

37. In an automatic musical instrument, a main source of power; a player action; means providing a windway connecting the two ;7 and flexible means interposed in said windway and cooperating with a wall thereof for governing communication between said source of power and player action.

38. In an automatic musical instrument. a. main source of power; a player action; means providing a windway connecting the two; and regulator means including a flexi ble diaphragm interposed in said windwa and cooperating with a wall thereof for controlling the pressure applied to said player action;

39. In an automatic musical instrument, a main source of power; a player action;

ble diaphragm interposed for controlling communication therebetwcen, said diaphragm being influenced by the pressures maintained in said windway to close communication therebetween, and means to influence said diaphragm toward open position.

41. In an automatic musical instrument, a main source of power; a player action;

means providing a windway connecting the two; and means including a flex ble (llu,-

phragm interposed in said windway for con trolling communication therebetween. said diaphragm being influenced by the pressures maintained in said windway to close commu nication therebetween, means to influence said diaphragm toward open position, and means to vary the force exerted by said last named means.

42. In an automatic musical instrimient, a main source of power; a player action; means providing a windway connecting the two; and means including a flexible diaphragm interposed in said windway for controlling communication thercbetwcen. said diaphragm being influenced by the pre ires maintained in said windway to close (H.21- munication therebetween, means to imiucnce said diaphragm toward open position, and means to vary the force exerted b" said last named means by substantially or met increments.

43. In an automatic musical i: "-runient, a main source of power; a player action; means providing a windway connecting the two; and means including a flexible diaphragm interposed in said windway for controlling communication therelzetwecn id diaphragm being influenced by the prc sures maintained in said windway to close connnunication therebetween, means to influence said diaphragm toward open position. and means to vary the force exerted by said last named means by substantii continuous progression.

14. In an automatic musical instrument, a main source of power; a player action: means providing a windway connecting the two; and means including a flexible diaphragm interposed in said windway for controlling communication thcrebetween, diaphragm being influenced by the pres ares maintained in said windway to close con1- munication therebetween, means to influence said diaphragm toward open position, and separate means to vary the force exerted v in one direction; .5

by said last named means either by substantially distinct increments, or by substantially continuousprogression, said means being operable separately or concurrently;

45. In an automatic musical instrument, a main source of power; a player action; means providing a windway connecting the two; and regulator means including a flexible diaphragm interposed in said windway for controlling communication therebetween, said diaphragm being influenced by the pressures maintained in said windway to close communication therebetween; and pneumatic means exerting a force in the opposite direction on said diaphragm to influence the same toward open position;

e6. In an automatic musical instrument, main source of power; a player action; means providing a wiiidway two;-regulator means including a throttle valve for controlling communication therebetween, said valve comprising a diaphragm having areas exposed to the respective pressures maintained in said windway on either side thereof whereby said valve is influenced: in one direction; and means for influencing I said valve in an opposite direction. 7

47. In an automatic musical instrument, a main source of power; a player action; means providing a windway between the two; regulator means including a throttle valve for controlling communication therebetween, said valve comprising adiaphragm having areas exposed to the respective pressures maintained in said windway on either side thereof whereby said valve is influenced in one direction; and means for influencing said diaphragm in the opposite direction with a substantiallyconstant force.

t8. in an automatic musical. instrument, a main source of power; a player action; means providing a windway between the two, regulator means including a throttle valve for controlling communication therebetween, said valve comprising a diaphragm having areas exposed to the respective pressures maintained in said windway on either side thereof whereby said valve is influenced and pneumatic means tor exerting an opposed force on said diaphragm.

e9. In an automatic musical instrument;

main source of power; a player action; means providing a windway between. the two; regulator means including a throttle valve for controlling communication there'- between said valve comprising a diaphragm having areasexposed to the respective pressures maintained in said windway on either side thereof whereby said valve is influenced in one direction; and pneumatic means for exerting an opposed substantially constant force onsaid diaphragm.

50. In an automaticmusical instrument,

between the a main source of power; a player action; means providing a windway between the two; regulator means including a throttle valve for controlling communication therebetween, said valve comprising a diaphragm having portions of its area exposed respectively to the pressures maintained in said wiiidway whereby said valve is influenced in one direction; and pneumatic iiiieans acting on said diaphragm and exerting a substantially constant force in theopposits direction.

. 51. In an automatic musical instrument, a main source of power; a playeraction; means providing a windway between the two; regulator means including a throttle valve for controlling communication therebetween, said valve comprising a diaphragm having portions of its. area exposed respectively'to the pressures maintained insaid windway whereby said valve is influenced in one direction; and pneumatic means act ing on said diaphragm for maintaining'sub stantially constant any selected pressure.

Inan automatic musical instrument, r

main source of power; a'player action; means providing a windway between the two; regulator means including a throttle valve for controlling communication therebetween, said. valve comprising a flexible diaphragm having areas acted upon by opposed pneumatic forces.

53. Expression controlling apparatus for automatic musical instruments, including a tree" floatingdiaphragm for controlling the passage oi air through a windway, said diaphragm of pressure therein.

54 Regulator means for automatic inusi cal instruments, comprising three bodies of air at diiierent pressures acting upon one another; and movable means for separating said bodies and for controlling communication between two of said bodies. V

55. Regulator means for automatic musi cal instruments, comprising threebodies of air at difierent pressures acting upon one being directly responsive to changes another; and'fiexible means for separating 7 In testimony whereof, I have signed my nameyto this specification tl isSth Clay of October, 1924c. e

CHARLES F. STODDAR-D; 

